JPH07224666A - V-type multi-cylinder two-cycle engine - Google Patents

Abstract

PURPOSE:To provide a V-type multi-cylinder two-cycle engine that is able to promote its miniaturization, aside from compactification, in realizing the rational setup of a scavenging valve. CONSTITUTION:In this V-type multi-cylinder two-cycle engine 1 to be made up of installing a scavenging valve 12 in each of interconnecting passages 11 making each crankcase 7 of respective cylinders be connected to each other via each scavenging bypass passages 10 and also each crankcase 7 and these scavenging bypass passages 10 be connected to each other, this scavenging valve 12 is set up in a V bank in series. The scavenging valve 12 being installed at each cylinder of this V-type multi-cylinder two-cycle engine 1 adopting a scavenging bypass system is srationally set up in the V bank or a dead space. Therefore, the effective utilization of a space is well promoted, whereby the miniaturization and compactification of this engine 1 are thus achievable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-type multi-cylinder two-cycle engine adopting a scavenging valve system.

[0002]

2. Description of the Related Art A marine engine is required to have a small and lightweight two-cycle engine due to the limitation of installation space.
Among them, a crank chamber compression type that can be further downsized is desired. Further, recently, development of a two-cycle diesel engine having high thermal efficiency has been promoted.

By the way, the so-called scavenging bypass system may be adopted not only for the two-cycle engine for marine vessels but also for other two-cycle engines for the purpose of preventing contamination of the crank chamber and reducing intake noise.

FIG. 5 shows a vertical cross section of an in-line multi-cylinder two-cycle engine 101 adopting the scavenging bypass system.
In the cycle engine 101, the crank chambers 107 of the respective cylinders arranged in series in the direction perpendicular to the plane of the drawing are configured to be communicable with each other via the scavenging bypass passage 110 and the communication passage 111, and the respective communication passages 111 are provided with the respective cylinders. A scavenging valve 112 is provided for each. In FIG. 5, 10
2 is a cylinder body, 103 is a piston, 105 is a connecting rod, 115 is a cylinder head, 120 is a reed valve, 121 is an intake manifold, and 122 is an exhaust manifold.

The scavenging valve 112 provided for each cylinder is integrally opened / closed by a driving means (not shown) according to the engine speed or the like, whereby the crank chambers 107 are selectively communicated with each other. The scavenging air (air) is supplied from the crank chambers 107 of the other cylinders to the crank chambers 107 of the cylinders whose pistons have moved to the upward stroke, bypassing the scavenging air (air). Planned.

[0006]

Therefore, in a multi-cylinder two-cycle engine for an outboard motor, for which miniaturization is required, it is desirable that this is a V-type multi-cylinder type,
When adopting the scavenging bypass method in such a V-type multi-cylinder two-cycle engine, the arrangement of the scavenging valve provided for each cylinder becomes a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a V-type multi-cylinder two-cycle engine in which a rational arrangement of scavenging valves can be realized to reduce the size and size. To provide.

[0008]

In order to achieve the above object, the present invention provides a communication passage for connecting the crank chambers of the cylinders to each other via a scavenging bypass passage, and for connecting the crank chambers to the scavenging bypass passage. In a V-type multi-cylinder two-cycle engine in which a scavenging valve is provided for each, the scavenging valve is arranged in series in the V bank or in the vicinity of the air intake portion.

[0009]

According to the present invention, in the V-type multi-cylinder two-cycle engine adopting the scavenging bypass system, the scavenging valve provided for each cylinder is reasonably arranged in series in the V bank or in the vicinity of the air intake section. , The space can be effectively used, and the V-type multi-cylinder two-cycle engine can be made compact and compact.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan sectional view of a V-type multi-cylinder two-cycle engine according to a first embodiment of the present invention (plan sectional view of an outboard motor), and FIG. 2 is a sectional view taken along line AA of FIG. 3 is a side view of an outboard motor including the same two-cycle engine.

An outboard motor 50 shown in FIG. 3 is attached to a rear plate 60a of a hull 60 by a clamp bracket 51, and a V-type multi-cylinder two-cycle engine 1 according to the present invention is provided in a housing 52 above the hull. It is stored.
Further, a propulsion device 53 is provided below the outboard motor 50, and the propulsion device 53 generates a required propulsive force by a propeller 54 which is rotationally driven by the two-cycle engine 1.

Details of the structure of the two-cycle engine 1 according to the present invention will now be described with reference to FIGS. 1 and 2.

The two-cycle engine 1 according to this embodiment has a V
A 6-cylinder water-cooled 2-cycle diesel engine, in which a total of six cylinders 2a forming a V shape and facing each other are arranged side by side in the vertical direction (direction perpendicular to the plane of FIG. 1). . A piston 3 is fitted in each cylinder 2a so as to be slidable in the horizontal direction, and the piston 3 is connected to a crankshaft 4 which is long in the vertical direction via a connecting rod 5. A total of six crank chambers 7 are formed for each cylinder inside a crankcase 6 connected to the cylinder body 2. The crankshaft 4 is rotatably supported in these crank chambers 7. It is stored.

Further, the cylinder body 2 has a scavenging passage and an exhaust passage 8 which are not shown for each cylinder. As shown in FIG. 1, the exhaust passage 8 includes the cylinder body 2
The cooling jackets 9 which are arranged in the V bank and which are also arranged in the V bank are integrally provided on the upper portion of the cooling banks 9 in the vertical direction (see FIG. 2).

Thus, in this embodiment, the cylinder body 2
In the V-bank, a scavenging bypass passage 10 which is long in the vertical direction (see FIG. 2) is integrally formed below the exhaust passage 8, and the scavenging bypass passage 10 and the crank chamber 7 of each cylinder are formed. Can be communicated with each other by a communication passage 11 provided for each cylinder.
2 are provided respectively.

As shown in FIG. 2, the six scavenging valves 12 are attached to a common valve shaft 13 which extends through the communication passage 11 and which is long in the vertical direction, and are arranged in series in the vertical direction. A driving arm 14 is connected to the upper end of the. The valve shaft 13 is driven by a drive mechanism (not shown) including a stepping motor, and the drive of the drive mechanism is controlled by an engine control unit (ECU) (not shown).

On the other hand, as shown in FIG. 1, a cylinder body 2 is covered with a two-divided type cylinder head 15, and a vortex chamber 16 communicating with each cylinder 2a is formed in the cylinder head 15. ing. An injector 17 and a glow plug 18 whose tip faces the vortex chamber 16 are screwed to the cylinder head 15 for each cylinder.

Further, the crankcase 6 is formed with an air introducing port 19 opening to each crank chamber 7, and each air introducing port 19 has a lead for allowing only a flow of air toward the crank chamber 7. A valve 20 is provided. The housing 52 is provided at the air inlet 19 of each cylinder.
An intake manifold 21 that opens inside is connected.

Thus, in the V-type two-cycle engine 1 adopting the scavenging bypass system, the engine control unit (ECU) uses the engine speed etc. as a parameter.
When a drive mechanism (not shown) is controlled, the valve shaft 13 is rotated by the drive mechanism and all the scavenging valves 12 are integrally opened and closed in the communication passage 11. And the scavenging valve 12
When opened, all the crank chambers 7 are in the scavenging bypass passage 10
And, the scavenging air (air) is supplied from the crank chambers 7 of the other cylinders to the crank chambers 7 of the cylinders that have communicated with each other via the communication passage 11 and the piston 3 has moved to the upward stroke,
As a result, the backflow of the combustion gas from the cylinder 2a is reduced to prevent the crank chamber 7 from being contaminated, and the intake noise is reduced due to the reduction of the air supply ratio. Also, cylinder 2
Since the burned gas remains in a, the temperature in the cylinder 2a does not decrease, and the combustion knock noise due to the ignition delay is reduced.

In the above, in the present embodiment, the scavenging valve 12 and the scavenging bypass passage 10 provided for each cylinder are rationally arranged in the V bank which is a dead space, so that the space can be effectively used and the V The size of the mold two-cycle engine 1 can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a plan sectional view of a V-type multi-cylinder two-cycle engine according to a second embodiment of the present invention (plan sectional view of an outboard motor).
In this figure, the same elements as those shown in FIG. 1 are designated by the same reference numerals, and description thereof will be omitted below.

The two-cycle engine 1 according to this embodiment is also a V-type six-cylinder two-cycle diesel engine similar to that of the first embodiment, and the side surface of the air intake portion thereof, that is, the air introduction port 19 of the crankcase 6 is provided. A scavenging bypass passage 10 that is long in the up-down direction (the direction perpendicular to the plane of FIG. 4) is integrally formed laterally, and the scavenging bypass passage 10 and the crank chamber 7 of each cylinder are provided for each cylinder. Communication passage 11
The communication passage 11 is provided with a scavenging valve 12 (shown by a chain line in FIG. 2).

The above six scavenging valves 12 are connected to the communication passage 11
A freely rotatable valve shaft 13 extending vertically through the valve shaft 13
, And they are arranged in series in the vertical direction.

Thus, also in the present embodiment, the scavenging valve 12 and the scavenging bypass passage 10 provided for each cylinder are rationally arranged on the side surface of the air intake portion which is a dead space, so that the first embodiment In addition to the effect similar to the above, the air introduced from the crank chamber 7 of the other cylinder through the scavenging bypass passage 10 and the communication passage 11 can easily join with the air sucked through the intake manifold 21 and the reed valve 20. Can also be obtained.

In the above, the present invention is particularly applied to the V type 6 for outboard motors.
Although the example applied to the two-cylinder cylinder diesel engine has been described, it goes without saying that the present invention includes any other V-type multi-cylinder two-cycle engine adopting the scavenging bypass system.

[0028]

As is apparent from the above description, according to the present invention, the crank chambers of the cylinders are communicated with each other through the scavenging bypass passages, and the communication passages for communicating the crank chambers with the scavenging bypass passages are provided. In a V-type multi-cylinder two-cycle engine having a scavenging valve for each, the scavenging valves are arranged in series in the V bank or in the vicinity of the air intake section, so that a reasonable arrangement of the scavenging valves is realized and the V
It is possible to obtain the effect that the multi-cylinder two-cycle engine can be made smaller and more compact.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a V-type multi-cylinder two-cycle engine (plan sectional view of an outboard motor) according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a side view of the outboard motor.

FIG. 4 is a plan sectional view of a V-type multi-cylinder two-cycle engine according to a second embodiment of the present invention (plan sectional view of an outboard motor).

FIG. 5 is a vertical cross-sectional view of a conventional V-type multi-cylinder two-cycle engine.

[Explanation of Codes] 1 V type multi-cylinder 2-cycle engine 7 Crank chamber 10 Scavenging bypass passage 11 Communication passage 12 Scavenging valve

Claims (1)

[Claims] 1. A V-type multi-cylinder in which the crank chambers of the respective cylinders are communicated with each other via a scavenging bypass passage, and a scavenging valve is provided in each of the communication passages for communicating the respective crank chambers with the scavenging bypass passage. A V-type multi-cylinder two-cycle engine, wherein the scavenging valve is arranged in series in a V-bank or in the vicinity of an air intake section in the two-cycle engine.